森林产权体系构建设想

森林产权体系构建是深化林业经济体制改革的关键。提出对国有森林资源,按照“政企分开”、“两权分离”的原则界定产权关系;对集体森林资源则宜按“股份所有,公司经营”的设想,实现产权界定;并提出了森林产权体系构建时必须注意的几个问题。     

新疆农九师一六七团防护林建设存在的问题及对策

阐述新疆农九师一六七团防护林建设所取得的成效,分析防护林建设存在问题,并提出相应的对策和建议.     

营林技术对林业有害生物的控制效果探析

指出了作为生态环境的主体,在环境保护过程中,森林资源发挥着关键性的作用。然而,随着社会经济的不断发展,对森林资源的乱砍滥伐现象也变得越来越严重,这就威胁了人们的生存与发展。因此,加强林业资源的保护具有重要的现实意义。基于此,围绕营林技术进行了分析,就其对林业有害生物的控制效果进行了探究,提出了相应的对策。     

Leaf litterfall concentrations and fluxes of elements in deciduous tree species

The influence of tree species and soil properties on leaf litterfall concentrations and fluxes of elements were studied in three mixed deciduous forest stands. Leaf litterfall fluxes of sixteen elements were measured during autumn defoliation in 100 to 150 yr old individuals of Fagus sylvatica L., Quercus robur L., Carpinus betulus L., Tilia cordata Mill, and Acer platanoides L. Compared to throughfall and precipitation, leaf litterfall dominated the flux of P, Ca, Mn, N and Mg (in decreasing order) to the soil below the tree canopies. For K and especially S and Na, however, the importance of leaf litterfall input to the total fluxes was small. Fluxes and especially concentrations of Ca, Mg, K, P and partly N were positively related to base saturation of the soil, while Mn was negatively related due to a higher mobilization rate and plant uptake of this element on acid soils. Litterfall fluxes for C. betulus were strongly positively influenced by base saturation and fluxes were usually higher than for F. sylvatica and Q. robur at the richest site. Quercus robur had often the lowest fluxes, especially of Ca and Mg. Tilia cordata had the highest leaf litter concentrations in twelve of the sixteen elements, and the highest fluxes particularly of N and K. Acer platanoides had the highest or among the highest concentrations and fluxes of Ca, Zn and Mn. The concentration of Al in C. betulus leaf litterfall, was about five times higher than in all other tree species at all sites.     

冀北山地杨桦次生林林分空间结构研究

在木兰林管局桃山林场选取面积为100 m×100 m的杨桦次生林样地,以每株林木树高、胸径和坐标为基础数据,运用混交度、大小比数和角尺度等林分空间结构参数分析了杨桦次生林的空间结构特征。结果表明:(1)该林分中山杨Populus davidiana和白桦Betula platyphylla在株数和断面积比例上占优势,为林分内优势树种;(2)林分各混交类型的比例相差不大,林分整体呈中度混交状态;(3)林分优势木和亚优势木相对较多,基于胸径、树高得到的平均大小比数结果基本一致,均能客观反映林分的分化规律;(4)林分平均角尺度为0.504,属于随机分布,林下伴生树种以集聚分布为主,但优势树种的随机分布趋势起决定作用。     

生态经济林经营模式

在我国丘陵山区开展以经济林为骨干项目的多种经营,是繁荣农村经济的一项战略措施。生态经济林业就是遵循自然规律和经济规律,按照生态学和生态经济学的原理,运用系统理论与系统工程的方法,组织经济林生产建设事业。它的任务是为制定经济林生产发展战略规划:为经济林栽培经营提供指导理论和方法。生态经济林的实施主要是通过区划和规划。生态经济林经营模式,有网络结构模式和立体经营模式之分。前者是一个地域生态系统的整体结构中,经济林作为一个子系统的位置,后者是具体林分结构的立体经营模式,两者是相关联的。     

关于对林木资产核算的初探

森林资源资产化管理已成为我国林业理论和实务工作者们普遍关注的问题,森林资源资产化管理的关键就是要将森林资源作为一种有价值的资产加以经营和管理,而森林资源资产的核算是资产化管理的基础;同时,鉴于森林资源资产是一个综合的概念,包括了林木、林地、森林景观等,其中林木资产是主体,因此,如何做好林木资产的会计核算工作就成为森林资源资产化管理的关键。     

两种热带森林覆盖变化检测方法比较研究

[目的]以热带森林复杂区域为对象,对两种缨帽变换“衍生数据”检测热带森林变化的方法的优劣进行比较.[方法]对两期数据进行缨帽变换,同时结合黑暗对象掩膜与局部直方图阈值提取等方法,获取亮度、绿度、湿度指数组合(MKT)和干扰指数(DI).采用MKT差值(MKT-D)、干扰指数差值(MDI-D)进行变化信息识别,然后,根据植被覆盖与亮度、绿度、湿度之间的变化关系,通过决策树分类提取变化信息,最后,对不同检测结果进行验证与比较分析.[结果]结果显示两种方法都能检测出森林内部的细微变化,但对小图斑变化,MKT-D检测优势明显,且MKT-D的kappa系数为0.763 0,MDI-D的kappa系数为0.655 9,两者相比,MKT-D方法优于MDI-D方法.[结论]MKT能够增强短波红外与近红外波段对森林变化信息的敏感性,有效地消除噪声等非目标信号,突出目标信号,此外,MKT-D为RGB彩色图像,更利于变化信息的目标提取与解译.     

Predicting the Dairy Cow Somatic Cell Number of Ningxia Area Based on ARIMA Model

Through dairy herd improvement (DHI) data analysis to predict somatic cell count (SCC) of Ningxia area in time, which providing a reference for the prevention and treatment of mastitis in dairy cows, making the DHI data more effective and timely in guiding the dairy industry production. Using the difference method to make the average cow somatic cell data form September 2011 to February 2016 stabled, then used the seasonal ARIMA model to analysis, fitting and forecasting data. The auto.arima function of R software had been used to calculate the optimal time series that finally confirmed the model was ARIMA (1,1,0)(1,1,0)_[12], AIC was -3.67. The Acf test showed that the residual had no significant autocorrelation; Ljung-Box test showed that all P-value>0.5, indicating that the residual was white noise, and this model could be used to make predication for the next 24 months. The forecast function of the R software was used to predict the dairy cows SCC from March 2016 to February 2017, and the forecast map was drawn. The predicted results showed that the SCC of the entire Ningxia area were showing a downward trend. The SCC would be the least in January 2017,and the predictive value was about 253 100 per mL. It would be the largest in March 2016, was about 439 600 per mL. The results also showed that the dairy cows SCC in Ningxia was higher than the critical value of 20 million of subclinical mastitis. It suggested that the prevention and treatment of dairy cow mastitis need to be strengthened in Ningxia area. At the same time, if the data of the dairy cows SCC was added in timely, the data model should be updated to make it more close to the true value, which would be more meaningful to the actual instruction.     

对北京市公益林市场化经营的思考

北京市的公益林作为传统意义上的公共物品，一直以来由全市各级政府投资建设，成本高，效率低，代价大。因此，提高公益林的经营效率和质量，对于北京市公益林的持续、健康发展至关重要。笔者就如何在北京市公益林的经营中引入市场机制进行思考，并力求构建一个较为合理的公益林市场化经营模式。